Elevator control system



8 Sheets-Sheet 1 y March 11, 1958 D. SANTINI ETAI.

ELEVATOR CONTROL SYSTEM Filed 001'.. 22. 1956 Fig.2.

March 11, 1958 Filed Oct. 22, 1956 D. SANTINI ErAL ELEVATOR CONTROL SYSTEM suRs was zum :oo

8 Sheets-Sheet 2 Common Crcus March 11, 1958 D. sAN'TlNl ErAL ELEVATOR CONTROL SYSTEM 8 Sheets-Sheet 3 Filed 00's. 22, 1956 OQO 2.o MHWM L SET- M March 11, 1958 D. SANTINI Erm. 2,826,270

ELEvAToR CONTROL SYSTEM Filed oct. 22. 195e a sheets-sheet 4 March 1l, 1958 D. sANrvlNl Erm. l 2,826,270

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' ELEvAToR CONTROL SYSTEM Filed Oct. 22, 1956 8 Sheets-Sheet 6 Mrch 11, 1958 l D. SAN-:jimv Erm. 4 2,826,270 ELEVATOR coNTRoL SYSTEM v 8 Sheets-Sheet 7 Filed oct. 22. 195e March 11, 1958 D. SANTINI ETAL- ELEVATOR CONTROL SYSTEM Filed 001:. 22. 1956 8 Sheets-Sheet 8 United States Patent Oice 2,826,270, Patented Mar. 11, 1958 ELE-vA'roR eoNTRoL SYSTEM Danilo Santini, Tenatly, and John Suozzo, Paramus, N. I., assgnors to Westinghouse Electric Corporation, East Pittslnirgh, Pa., a corporation of Pennsylvania Application October 22, 1956, Serial No. 617,444 1i claims. (Ci. 18a- 29) This invention relates to elevator control systems and it has particular relation to" elevator control systems for a plurality of elevator cars arranged in a bank and provided with dispatching equipment for controlling the dispatch` of elevator cars' from one or more dispatching floors.

The prior art discloses' two major types of dispatching equipment. In one type the dispatching of elevator cars is controlled by factors such as the position and direction of elevator cars and the registration of calls calling for elevator service. A` second type of dispatching equipment isl time cor'itroll'edA for the purpose of establishing a' time interval between the dispatching of each pair of successive elevator cars.

Although aspects of the invention are applicable to elevator systems employing each of the above-mentioned types of dispatching equipment, the invention is particularly desirable for elevator systems employing both types of dispatching equipment' and will be described with reference to such a system.. The invention further may be applied to an elevator system of the automatic type which does not require elevator car attendants, or it may be applied to an elevator system wherein attendants are provided in the elevator cars.

For eicientpoperation of an elevator system wherein a plurality of elevatorcars are arranged in a bank, the elevator Icars should be adequately spaced from each other. If the spacing of the elevator cars is lost and the elevator cars become hunched, the elliciency of the elevator system is decreased. Furthermore, an elevator carshould not be permitted to stand idle at a terminal iloor for an excessive period of time when its services are desired elsewhere.

In accordance with the invention, an elevator car must be in a zone of landings adjacent the terminal landing whichy it is approaching before a call for elevator service for a landing behindthel elevator car is permitted to start a second elevator car towards the same terminal landing.

The .invention Ialso contemplates a modification of the dispatchin'g'interval in the event that an undesirably large number of elevator cars become set for travel in the same direction. In a preferred embodiment of the invention, dispatching equipment for establishing dispatching intervals for elevator cars lis eiective only in the presence of registration of certain calls for elevator service andis not effective ,in therpresrence of registration only of certain other calls for elevator service. Thus, dispatch'- ving*.equipment for Lcontrolling the dispatch of elevator cars from a lower terminal landing is not effective if only landing down calls areregistered.

It is, `therefore, an object of the invention to provide an improved elevator system wherein an elevator car is assumed to be at a terminal landing when it is in a zone of landings adjacent to the terminal-landing.

It is another object of the invention Vto fprovide an improved elevator system wherein an elevator car must be in a zone of landings adjacent the terminal tlandingvvli-ich it is approaching before call registration behind the elevator car can start a second elevator car from the other terminal landing.

It is also an object of the invention to provide an improved elevator system wherein a dispatching time interval is modied in the event that a large number of elevator cars are conditioned to travel in the same direction at the same time.

It is a further object of the invention to provide an improved elevator system wherein dispatching equipment of the time interval typ'e is eifective only in lthe presence of said time in all call registrations for elevator service.

Other objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which:

Figure l is a schematic view in straight line form, with parts shown in perspective and parts broken away, showing operating circuits for an elevator car;

Fig. 1A is a schematic view of relays and contacts employed in the system of Fig. l. The contacts and coils of the relays in Fig. lA are in horizontal alignment with the corresponding contacts and coils in Fig. l;

Fig. 2 is a schematic view in straight line form of landing call and other circuits suitable for an elevator system;

Fig. 3 is a view in elevation, with parts broken away, of elevator apparatus which may be employed in the system of Fig. l;

Figi. 4 is a schematic view of a stepping relay which may be employed in an elevator system embodying the invention;

Fig. 5 is a schematic view in straight line form showing certain control circuits for the elevator system embodying the invention;

Figs. 6, 7 and 8 are schematic views in straight line form showing control circuits for an elevator system embodying the invention; and,

Figs. 6A, 7A and 8A are schematic views of certain of the relays employed respectively in Figs. 6, 7 and 8. If Figs. 6, 7 and 8 are placed in side by side relationship respectively with Figs. 6A, 7A and 8A, the corresponding coils and contacts are substantially in horizontalalignment.

In order to simplify the presentation of the invention, the invention will be applied insofar as practical to the elevator system shown in the Keiper et al. Patent 2,597,- 586 which issued May 20, 1952. insofar as practical, the same reference characters will be employed to designate similar components in the patent and in the present patent application. In addition, the conventions set forth in the Keiper et al. patent will be followed as closely as practical.

The following relays and switches are shown in the aforesaid Keiper et al. patent and in the present patent application. For certain of the relays additional contacts may be provided as referred to below.

Switches and relays specific to car A:

AU-Up switch AD-Down switch AV-Speed relay ANI-Running relay AG-Inductor holding relay AE-Inductor slowdown relay AF-Inductor stopping relay AT-Car call stopping relay A'I-Reversing relay AS-Landing call stopping relay AW-Up relay AX-Down relay 'AK-Landing call above relay A14-High call reversal relay 3 AH-Car call above relay AI-Car call below relay Relays common to all cars:

TUR to 6UR-Landing up registering relays 2DR to 7DR-Landing down registering relays 1-Up peak relay Z-Down peak relay S-Upper terminal next relay 6-Lower terminal next relay K-Landing call relay In addition, the following relays are shown in the attached drawings:

"Relays specific to car A:

A12-Upper terminal relay A13-Lower terminal relay AL-Car call relay AXU-Upper zone relay AXD--Lower zone relay v A931-Start up relay A9414tart down relay A70T--Delay relay Relays common to all cars:

G-Landing up call relay G- Landing down call relay UTA- Up timing relay DTA- Down timing relay FIGURE l l Fig. 1 is similar to Fig. l of the aforesaid Keiper et al. patent with the following exceptions.

In order to simplify the presentation, it will be as- .sumed that the elevator car A when traveling down does not stop and reverse at a landing above the lower terminal landing. With this assumption, the contacts A13-4, the switch ATE and the contacts A13-2 and AM3 illustrated in Fig. l of the aforesaid Keiper et al. patent are not here required and are not reproduced for the same circuit. By inspection of Fig. 1 it will be observed that the down relay AX has its energization controlled .only by the break contacts AUS and AWZ and by the `limit switch A3013. It will be recalled from the Keiper et al. patent that this limit switch is open only while .the elevator car A is adjacent the lower terminal landing.

In addition, a delay relay A70T is provided which is energized by make contacts AM3 of the running relay AM and a switch ASW4 in parallel. The switch ASW4 is closed only while the elevator car A is at either of its terminal landings, in this case, the first and seventh landings. When deenergized the delay relay A70T has a substantial time delay in dropout which may be of the order of five seconds. This delay is measured at each of the intermediate landings at which the elevator stops for the purpose of providing adequate time for passengers to leave or enter the elevator car.

With the manually-operated single-pole double-throw switch ASW3 in the position illustrated in Fig. l, the relays AU, AM and AD are controlled in precisely the same manner discussed in the aforesaid Keiper et al. patent. If the switch ASW3 is thrown to its remaining position, the system is arranged for automatic operation. Under these circumstances, closure of the break contacts A70T1, the make contacts A931-1 or the make contacts A941-1 completes a shunt across the switch ASW and its contact ASWl to control the energization of the relays AU, AM and AD. The contacts A931-1 and A9414 are associated respectively with a start up relay A931 y Fig. 2 is similar to Fig. 2 of the Keiper et al. patent; however, certain of the relays are provided with additional contacts which will be discussed below.

FIGURES 3, 4 AND 5 Figs. 3, 4 and 5 are similar to Figs. 3, 4 and 5 of the aforesaid Keiper et al. patent with a few exceptions. Consequently, a detailed description of these figures is not here required. The contacts on certain of the relays shown in Fig. 5 may be modified as discussed below. In addition, the construction'of a row of contact vsegments on the selector A37 is modified as fset forth below. Finally, two relays 10)A and 200 are added. The landing up call relay is connected across the direct-current buses L-l-S and L-5 through break contacts 1UR3 to 6UR3 of the landing up registering relays 1UR to 6UR. The landing down call relay 200 Vis connected across the same buses in series with the break contacts 2DR3 to ,'7DR3- ofthe landing down registering relays 2DRH to .'7DR. Consequently registration of a landing up call deenergizes the relay 100 whereas registration` of a landing down call deenergizes the relay 200.

FIGURE 6 Fig. 6 shows the car buttons A1C to,A7CV and associated circuits which are similar to those shown in'Fig. 6 of the aforesaid Keiper et a1. patent with the following additions. By inspection of Fig. 6 it Will be noted Athat each of the car buttons is provided with an additional Contact AlCl to A'iCl, respectively. These additional contacts are `all connected to one terminal of the car call relay AL, the remaining terminal of the relay being connected to the bus L-6.

By inspection of Fig. 6 it will be noted that operation of the button A1C for the first landing connects the contact AlCl to the bus L+6 and consequently completes an energizing circuit for the car call relay AL. In a sirnilar manner, operation of any of the car buttons for another landing results in energization of the car call relay AL.

The down timing relay DTA is connected in series with break contacts A941-4, B941-4 and CSM-fl and with the anode T22A and cathode T22C of a control device T22 across the direct current buses L+6 and L-6. When the relay DTA picks up it closes its make contacts DTA3 to establish a holding circuit around control device T22.

The control device T22 may comprise any device suitable for control for the intended purpose. For example, it may be a hot-cathode or a cold-cathode electronic tube of the high vacuum or gaseous types. For present purposes, it will be assumed that the control device T22 is a cold-cathode gaseous discharge tube of the type commonly referred to as a thyratron.

The tube T22 has a control electrode T22G and the voltage appearing between the control electrode and the cathode T22C is equal to the sum of the voltages across a capacitor T23 and the secondary Winding of a transformer T24. The secondary winding of the transformer and the capacitor are connected in series with a resistor T25 across the buses L+6 and lli-6.

The transformer T24 has its primary winding connected across an adjustable portion of a voltage divider T26 and the Voltage divider is connected to a suitable valternating current source which may have a frequency 'of 60 cycles per second.

In order to discharge the capacitor T23 a resistor T27 is connected across the capacitor T23 and the secondary winding of the transformer T24 through four sets of make contacts in parallel. These are the make contacts A941-5, BMI-5, C941-5 and DTAZ.

The operating sequence of the down timing relay DTA now will be considered. Let it be assumed that a suitable source of alternating current is connectedl acrossv the vonage divider T26 and that the capacitor 'fzs is daenergized at the instant direct current volta'geis applied to the buses L+6 and L-6. Under such circumstances, the capacitor starts to charge ata rate determined primarily by the magnitude of the resistor T25. It will be assumed further that the relays A941, B941, C941 and DTA are all deenergized and drop out. The voltage 'across the vcapacitor T23 builds up until the sum of this voltage and the alternating voltage appearing across the secondary winding of the transformer T 24 is sufficient to tire the tube T22. lSuiiicient current now Vpasses through the tube to pick up the relay DTA and this relay closes its make contacts DTAS to establish4 a holding circuit around the tube T22; in addition, the make contacts DTA2 close to discharge the capacitor T23. Finally, make contacts DTAl, DTA4 and DTAS all close to indcate that a dispatching interval has expired.

Letit be assumed that the closure of the make contacts DTA1 results in the starting of the elevator car A inthe manner hereinafter described. Such starting is accompanied by pickup of the relay A941 and this relay opens its break contacts A94l-4 to interrupt the energization of the relay DTA. In addition, make contacts A941- close to maintain the discharge circuit for the capacitor T23.

The dropout of the relay DTA is accompanied by opening of the make contacts DTA2, DTA?, DTAI, DTA4 and DTAS, without immediate effect on the operation of the system. y K v As tllenelevator cary A leaves the upper terminal landing, the relay A941 is deenergized. This relay recloses its break contacts A941-4 without immediate effect on the operation of the system. However, the opening of the` make contacts A941-5 interrupts the discharge cir cuit, forlthe capacitor T23 and this capacitor starts to charge from the buses L+6 and L.-6. After the expiration of a suitable dispatching interval the capacitor T23 again is charged to a value sufficient to tire the tube T22. `This sequence is repeated during the operation of the elevator system. lt will be understood that the length of the dispatching interval may be ,adjusted by adjusting the portion of the voltage divider T26 which is connected across the primary winding of the transformer T24. n In an analogous manner the up timing relay UTA is connected across the buses ifi-6 and L- through the break contactsA931-3, B931`3 and C931-3 and through the anode and cathode of aY control device L22 which againy maybe in the form c-f a thy'ratron tube. Make contacts UTA3 ofl the relay UTA establish a holding circuit for the relay around the tube L22. The voltage across a capacitor L23 and the secondary winding of a transformer L24 in series is applied between the control electrode ofthe tube L22 4and the cathode of the tube. Thejcapacitor L23 is charged from buses L-land L-6 through the resistor LZS and the secondary winding of the transformer L24. v y

In order to discharge the capacitor L23 a resistor L27 is connected across the capacitor and the secondary winding of the transformer L24 through four sets of make contacts Vin parallel. These are the contacts A931-4, B931-4', C931-4 and UTA2. i

If the switch L is closed the primary winding of the transformer L24 is connected to a tap L29 for the purpose of connecting the primary winding across an adjustable portion of the voltage divider L26. This voltage divider is connected to a suitable source of alternating current which may have a frequency of 60 cycles per second. Since the portions of the circuits associated with the up timing relay UTA are similar to those associated with the down timing relay DTA, the operation of the relay UTA will be understood from the previous discussion of the operation of the relay DTA.

The circuits associated with the up timing relay UTA includes provisions for automatically adjusting the dispatching interval measured by the Vrelay UTA. To this maV irwin .be noted tirarmi, switch'. Lso isojcmineets the right hand terminal-of the primary winding of-.the transformer L24 to an adjustable tap L31 on the' voltage divider L26 through three sets of make contacts in parallel, namely the contacts AXIS, BX15 and CX15. These contacts are operated respectively by the down relays AX, BX and CX of the elevator cars A, B and C.

If the elevator carsl are properly distributed lor spaced, at least one of the sets of make contacts AXIS, BX15 and CX15 yare closed to establish a shunt across` a portion of the voltage divider. Since this increases the' current flowing through the voltage divider, it follows that the voltage applied to the primary winding of the transformer L24 is increased. The increased voltage applied to the transformer L24 decreases the dispatching interval measured by the relay UTA. Y V i Let it be assumed next that van abnormal spacing' of the elevator cars results in a condition wherein all f the elevator cars are set up for travel. Under such cou-v ditions, all of the mak-e contacts AXIS, BX15 and CX15 are open and the voltage` applied to the transformer L24 is reduced. Because of this reducti-on in voltage, a larger dispatching interval is measured by the relay UTA. This larger dispatching interval is effective for restoring the proper spacing of the elevator cars.

Under other conditions, other dispatching intervals may be desirable. For example, during off hours operation, such as those occurring during the night in an oice building, a shorter dispatching interval may be desired. Such an interval may 'be obtained by opening the manually operated switch L30 and closing the manually operated switch OH to apply a larger voltage across the primary winding of the transformer L24. During up peak operation a still shorter dispatching interval may be desired and this may be obtained if the switches L30 and OH are open `by closure of the make contacts 1-7 of the up peak relay to apply a still larger voltage across the primary winding of the transformer L24.

FIGURE 7 Energization and pickup of the upper zone relay AXU indicates that the elevator car A is in a zone of landings adjacent the upper terminal landing and is set for up travel. The number of landings to be included in the zone depends on the specific requirements of an elevator installation. For presentpurposes, it will be assumed that the upper zone includes the fifth and sixth landings.

By inspection of Fig. 7, it will be noted that the upper zone relay AXU is associated with contact segments located in a row of segments Ar2 to Ar6 which are provided in the selector A37 of Fig. 3. This row of contact segments has abr'ush A50 associated therewith for move'- ment in accordance with movement of the elevator car A. The brush is connected to the bus L-'-7. One terminal of the upper zone relay AXU is connected to a contact segment for each of the landings included in the upper zone. For the assumed conditions the terminal of the relay is connected to the contact segments ArS and Ar5 for the iifth and sixth landings respectively. The remaining 'terminal of the relay is'connected to the bus L+6 through make contacts AW11 which are operated by the up relay AW of Figi'.

The lower zone relay AXD when energized and picked up indicates that the elevator car A is in a lower zone of landings adjacent the lower terminal landing. The number of landings included in the zone depends on the -requirements Iof each specific elevator installation. For present purposes it will be assumed that the second and third landings arel included in the lower zone. One terminal Vof the relay AXD is conncctedto a contact segment for each of the landings in the lower zone, in this case the contact segments Ar2 and Ar3 for the second and third landings respectively. The remaining terminal of the lower zone relay AXDis connected to the bus "7 L+6-through the make contacts AX11 which are operated'by the down relay AX of Fig. l.

Thus if the elevator car A is set for up travel the make contacts AW11 are closed. If, at the same time, the elevator car is adjacent the fifth landing the brush A50 is in engagement with the contact segment ArS and completes with the make contacts AW11 an energizing circuit for the upper zone relay AXU.

If the elevator car A is set for down travel the make contacts AX11 are closed. vlf 'the elevator car A at the same time is adjacent the third landing the brush A50 is inengagement with the contact segment Ar3 to complete withthecontacts- AX11 an energizing circuit for the lower zone relay AXD. I

The upper terminalv relay A12 and the lower terminal relay A13 correspond respectively to the relays A12 and A13 of the aforesaidKeiper et al. patent. However, for 'present-purposes, it is assumed that the upper terminal relay A12 is connected across the direct current buses L4-7 and L-7 through a mechanically-operated switch ASWS which is closed only when the elevator car A is at the upper terminal floor. The lower terminal relay A13 is connected across the Abuses Ll7 and L-7 through a mechanically-'operated switch ASW6 which is closed only'when the elevator car A is at the lower terminal landing.

The high call reversal relay A14 is similar to that shown in the aforesaidv Keiper et al. patent `and is similarly energized.

When the elevator car A is at the lower terminal land ing the make contacts A136 of the lower terminal relay A13 are closed.v lf at the same time the contact 6A of the stepping relay 6 has selected the elevator car A as the next elevator car to leave the lower terminal landing an energizing'circuit for the lamp ANU is completed as follows:

L+6, A6, ANU, A13-6, L-6

The operationl of the stepping relay 6 is similar to that set forth in the aforesaid Keiper et al. patent. When the lamp ANU is illuminated it indicates that the elevator car A should be loaded and that it will be the next elevator car to leave the lower terminal landing. The lamp ANU may be a floor lantern located at the lower terminal landing or it may be a lamp located in the elevator car A.

Let it be assumed that the elevator car A is at the lower terminal landing (make contacts A13-6 are closed) and that it is selected as the next car to leave the lower terminal landing. If4 a suitable dispatching interval has elapsed since the last elevator car left the lower terminal landing the make contacts UTA1 of the up timing relay close. If a car call is registered in the elevator car A the make contacts AL1 of the car call relay AL close. lf a landing up call is registered from one of the landings the break contacts D-1 of the landing up call relay 100 close. Thus, an energizing circuit is established for the lamp ASU Ias follows:

u L-l-7, A6, UTA1, 100-1 or ALI, ASU, A13-6, L-7

The illumination of this lamp advises the car attendant, if one is used, that the elevator car is to start from or leave the lower terminal landing. It should be noted that if the only call for elevator service is a landing down call the contacts UTA1 are ineffective to start the elevator car-A.

. lf the elevator car A is on automatic operation, energization of the start up relay A931 is utilized to start the elevator car. This relay is connected for energization `at the same time as the lamp ASU. rAs shown in Fig. 7, the relay is connected in parallel with the lamp. When the relay A931 picks up `it closes its make contacts A931-2 to establish with the contacts A13-6 a holding circuit for the relay. Thereafter, the relay remains picked up until the elevator car A leaves the lower terminal landing Such departure of the elevator car results in opening of the make contacts A13-6 to deenergiae the relay. A931 and the lamp ASU. v I y,

If the elevator car A is at the lower terminal landing (make contacts A13-6 are closed), if the elevator car- A is selected as the next elevator car to leave the lower terminal landing (contact A6 is connected to the bus L+?) and if the elevator car is stopped (break contacts AM4 are closed), a number of additional circuits are eiectiveA for controlling the energization of the lamp ASU and the relay A931. These circuits control the connection of one terminal of the contacts AM4 to the contacts A6 and are dependent on the positions of the cars, the direction of travel of the cars, the running condition of the cars and call registration. Because of the number of these circuits, they may be best described in tabular form. First, it will be assumed that all three of the elevator cars A, B and C are in operation. Under such circumstances, a starting circuit is completed if any one of the items A, B, C, D or E of Group I is satisfied and if in addition any one of the items A, B, C or D of Group II is satised in the following tabulation:

Dispatchng from lower terminal floor A. ALL THREE CARS ARE IN OPERATION Group I:

A. Car B is in lower terminal zone (make contacts BXDI are closed) B. Car C is in lower terminal zone (make contacts CXDZ are closed) C. Car B is at lower terminal oor (make contacts B13-5 are closed) D. Car C is at lower terminal oor (make contacts C13-7 are closed) E. Cars B and C are both in service (switches B11-1 and C11-1 are closed with switches B11-2 and Clt-2 open) and one item A or B in each of the following sub groups occurs:

Sub Group 1 A. Car C is set for -down travel ('break contacts CWIS are closed) and any one of the following is also present: (a) A landing call is registered above the car C (break contacts CK2 are closed); (b) An up oor call is registered (break contacts 10G-3 are closed); (c) A car call is registered in the car C (make contacts CL4vare closed).

B. The car C is at the lower terminal'lloor (make contacts C13-11 are closed) Sub Group 2- A. The car B is set for down travel (break contacts BW12 are closed) and any one of the following is also present: (a) A landing c-all is registered above the car B (break contacts BKI are closed); (b) A11 up door call is registered (break contacts -2 are closed); (c) A car call is registered in the car B (make contacts BLS are closed) B. The car B is at the lower terminal floor (make contacts B13-10 are closed)l Group Il:

A. The car A has a car call (make contacts AL2 are closed) B. A oor call is registered (break contacts K1 are closed) C. Car B is at the lower terminal floor (make contacts B13-8 are closed), car C is running (make contacts CMS are closed) and car C is set for down travel (make contacts CX12 are closed) D. Car C is at the lower terminal oor (make contacts C13-9 are closed), car B is running (make contacts BM6 are closed) and car B is set for down travel (make contacts BX13 are closed) FIGURE 8 lf the elevator car A is at the upper terminal landing the make contacts Allof the upper terminal relay are closed. If, in addition, the elevator car A is selected as the next car to leave the upper terminal landing, the contact AS of the stepping relay 5 is connected to the bus L+8. The contact A5 is operated by the Vstepping relay e' in the manner set forth in the aforesaid Kciper et al. patent. Under these circumstances, the lamp AND is illuminated to indicate that the elevatorcar Ak is the next elevator car to -leave the upper terminal Ilanding and that the car should be loaded. The'lamp AND may 'be a floor lantern at the upper terminal landing or a lamp in the car A.

Let it be assumed that the elevator car A is at the upper terminal landing and that ithas 'been selected as the next elevator car to Aleave the upper terminal landing. lf -a dispatching interval has expiredfollowing the departure of the last elevator car to leave the upper terminal landing, the make contacts DTA1 of the down timing relay DTA close. If a car call is registered in the elevator car A the make contacts ALS of the car c/aII relay AL close. If a landing down call is registered from one of the landings of the building served `by the elevator cars, the break contacts 200-1 f the relay 200 close. Thus, an energizing circuit for the lamp ASD is completed as follows: n I L-i-, AS, DTAI, 261)-1 or ALS, ASD', A1 25, L-'S Illumination of this lamp, which mayv belocated in the car, indicates that the elevator car attendant should start the elevator car away from the upper terminal landing. It should be noted that ythe make `contacts DTAl are y,not enective to energize the lamp ASD if the only call registered in the system is a landing up call. o

vIf the elevator car A is on Iautorriatic operation the relay A941 is employed for controllingv the starting Vof theelevator car. This relay is energized at the same time as the lamp ASD conveniently by connecting the relay in parallel with the lamp. When thisrelay is ener.- gized it closes its make contacts A941-6 to complete vwith the make contacts A12-S a holding circuit for the relay. Consequently, the relay remains picked up until the elevator car Aleaves the upper terminal landing. The departure of the elevator car is accompanied by opening of the makecontacts A12-5 to deenergize the relay A941 andthelampASD. l o L, y

If the elevator car A is at the upperterminal landing (make contacts A12-5 -areolosedl and if itis selectedas the next elevator car toleave thel upper terminal landing (contact A5 is connected to thebus L +8) a number of circuits other than ,those associated `withvthemake contacts DTAlA control the departure oftheelevator car. Fihus lif the elevator car B also is at they uppery terminal landing (make contacts B12-6y are,closed)w-orylin the upper zone (make contacts BXUl are closed)r oir-if the elevator oark C is at the upper terminalrlanding (make contacts C12-7 are closed) or in thevupperzone (make contacts CXUZk are closed) a starting circuitA is come pleted.l Additional circuitsmare controlled by the positions or the elevator cars, Ythe directions in kwhich the, elevator cars Iare set to travelthe starting conditions ,of the elevator cars `and cal-l I registration. These additional circuits are best set forth, in tabular form. I Y t v Under the assumed conditions, if any one ofthe items A, B or C under the following Groiipl is satisfied and addition any one of thev items A ,or B under thefollowing Gronp ll is satisiied, an energizing circuit is completed for the relay A941 and the lamp ASD.

DISPTCHING FROM UPPER TERMINAL FLOOR Group I:

A. Car B is in the lower terminal zone (make contacts BXD3 are closed) n B. Car C is in rthe lower terminal zone (make contacts CXD4 are closed) C. Cars B and C are 'both set for up travel (make contacts BW14 and BW15 are closed) Group II: y

A. Car B is set for up travel (break contacts BX14 are closed) and does not have a down start signal (break contacts B941-2 are closed) and either: l. A car call is registered for the car A (make contacts AL6 are closed) or 2. A down floor callk is registered (break contacts 20G-2 are closed) and there is aoor call which is above the oar C (break contacts CK3 lare closed). Desirably this operation would respond only to a down oor call above the car C. However, the illustrated circuit is economical and provides satisfactory service. v B. Car C is set for up travel (break contacts CX16 are closed) and does not have a down start signal (break contacts C941-3 are closed) and either:

l. A car call is registered for the car A (make contacts AL7 `are closed) or 2. A down oor call is registered (break contacts 200-2 are closed) and a floor call exists which is above the car B (break contacts BK6 are closed).

Under lcertain `conditions the elevator car A may be reversed during up travel at a landing below the upper terminal landing. Under such circumstances, the reversed relay Al picks up in the manner set forth in the aforesaid Keiper et al. patent. Such pickup results in closure of the make contacts A13 and A14 of Fig. 8, and also results in the stopping or' the elevator car at an inter" mediate landing in thenianner set forth in the aforesaid Keiper et al. patent. As the elevator car stops, its direc tion `or travel is reversed in the manner described in the Keip'er et al. patent. ln addition, the break contacts AM7 close to 4complete with the contacts A13 and A14 an `energizing circuit for the lamp ASD and the relay A941. This `assigns the elevator car A to start from the intermediate landing in the down direction. It will be understood that the break contacts AM7 lare operated by the running relay AM `of Fig. l. v

Figures 6, 7 and 8 show corresponding circuits for the elevator `cars A, B and C which may be readily traced.

OPERATION In considering the operation of the system, it will be assumed initially that the manually-operated switch ASW3 is in the position, illustrated in Fig. l. Under such circumstances the car switch ASW is effective for controlling the operation ofthe elevator lcar A in precisely the same manner discussed in the aforesaid Keiper et al. patent. For this reason it should sufi'ice to corinne the discussion of the operation of the system to the effects of the modifications in operation introduced by the present invention. Let it be assumed first that the elevator car A -is at the lower terminal landing (make contacts Aji3-6 in Fig. 7 are closed) land that it is selected as the next elevator car to leave the lower terminal landing (Contact A6 is connected to the bus ifi-7). lt is assumed further that the elevator car E is yset for down travel (make contacts BXll :are closed) and that the elevator car B is adjacent the third landing (brush B engages contact segment B13). Under such circumstances, the lower zone relay BXD is picked up and the make contacts BXDI are close At this time it is assumed that a passenger or attendant in the elevator car A loperates car button A5C(Fig. v6) 'to register a ycall for the fth oor. Such an operation L-l-7, A6, BXDl, AL2, AM4, ASU and A931 in parallel,

i A13-6, `L--7 Consequently, the car attendant in the elevator' car A is notified by the illumination of the lamp ASU that he should start his elevator car.

It should be noted that the instruction to start the elevator `car A is obtained despite the fact that the elevator car` B has not yet reached the lower terminal landing. This advance starting `of the elevator car A `has been found todecrease the standing time *of the elevator system and thus to improve its eiciency.

- A somewhat' similar expedition of the starting of the elevatorcarsi's obtained at the upper terminal landing. For example, let it be assumed that the elevator car A is at the upper terminal landing (make contacts Al2-5 'in Fig. 8 are closed) and that it is selected as the next elevator car to :leave the terminal landing (contact A5 is connected to the bus L-l-S). lt is assumed also that the elevator car B is set for up travel (make contacts BWll are closed) and that the elevator -car B is adjacent the iifth landing (brush Bt) engages contact segment BrS). Under these circumstances the upper Zone rel-ay BXU is picked up and the make contacts BXUll are closed to complete the following circuit:

Li-s, A5, BXUi, Assi and Asn in paralisi, Aufs, L s

The illuminated llamp ASD advises the car attendant t start his elevator car A despite the fact that the elevator car B has not yet reached the upper terminal landing. Again this advanced starting of the elevator car A assists in decreasing the standing time of the elevator cars.

For the next sequence of operation, let it be assumed that the switch L30 (Fig. 6) is closed, that the elevator car A is at the first landing set for up travel, that the elevator car B is at the third landing set for up travel, and that the elevator car C is at the fourth landing set for up travel. Since these cars are all set for up travel, it follows that the down relays for these cars are all deenergized andthe make contacts AXlS, BXlS and CXS are all open. Since these contacts are open, a decreased voltage is applied to the primary winding of the transformer L24 and from the preceding discussion it follows that the dispatching interval measured by the up timing relay UTA is increased. Consequently, a longer dispatching time must elapse before closure of the make contacts UTAI, UTA4 and UTAS can assign another elevator car to leave the lower dispatching landing. This decreases the tendency of the elevator cars :to bunch in the up direction.

it will be recalled that the make contacts UTAl are effective only `if an up landing call is registered (break contacts 10G-1 are closed) or a car call is registered (make contacts ALl are closed). The contacts UTAl are ineffective if only a down landing call is registered. In a similar manner, the make Icontacts DTAi are effective only if a 4down landing call is registered (break contacts 20G-l are closed) or a car is registered (make contacts ALS are closed). The contacts DTAl are ineffective if only an up landing call is registered. These features further decrease the probability of bunching of thc elevator cars.

Let it be assumed next that the elevator car C is set for down travel at the fourth landing and that the elevator car A is selected as the next elevator icar to leave the upper terminal landing. The elevator car B is assumed to be -at the -lower terminal landing set for up travel. At this instant, a -down landing call is registered for the fifth floor. Such registration results in pickup of the landing down registering relay SDR to open the break contacts 5DR3 and thereby deenergize the landing down call relay 200. This relay closes its break contacts 200-2. In addition, break contacts SDRZ open (Fig. 5). Sincethe elevator car C is assumed to lbe adjacent the fourth landing, the opening of lthe break contacts SDRZdeenergizes the landing call above relay CK and this results Iin closure of the break contacts GKS. lnasmuch `as the `elevator car B is set for up travel, the break contacts BXM are closed. Also, the elevator car B does not have a down start signal and the break contacts B94l-2 consequently are closed. Consequently, the contacts B941-2, BXM, CK3 and Edil-2 are all closed. However, a circuit for energizing the start down relay A941 is not completed by :these contacts for the reason that the elevator car B is set for up travel (make contacts BXll are open) and the lower zone relay BXD consequently is deenergized and the make contacts BXDS are open. ln addition, the elevator car C is at the fourth landing which is above the lower zone of landings. Consequently, the lower zone relay CXD is deenergized and the make contacts CXD4 `are open. Finally, the elevator car C is set for down travel 4and 4the make contacts CWS of the up relay consequent-ly are open.

When the elevator car C reaches the third landing the brush yC50 engages the contact segment Cr3 to complete `with the contacts CX11 an energizing circuit for the lower zone relay CXD. This relay now closes its contacts CXD4 to complete the following energizing circuit: L-i-S, A5, 13941-2, BX14, CK3, 200-2, CXD4, A941 'and ASD in parallel, A12-5, L-S. Consequently, the elevator car A now receives a start signal. By delaying this start signal until the elevator car C is in the lower zone, a fourth deterrent is Aprovided against bunching of the elevator cars.

yIn the examples `thus far discussed, it has been assumed that the elevator system is on attendant operation. The eect of operation of the manually-operated switch ASW3 lto its upper position as viewed in Fig. l now will be considered. Such operation renders ineffective the lcar switch ASW.

The elevator cars continue to stop in precisely the same manner discussed in the aforesaid Keiper et al. patent. Let it be assumed that the elevator car A stops lat the fifth landing. lt will be recalled that the switch ASW4 is open while the car is at intermediate landings. As the elevator car comes to a stop, the make contacts AM3 of the running relay open and the delay relay A70T starts to time out. During the period required for the relay A70T to time out the elevator car doors can be opened and the passengers discharged or loaded as required.

To conserve space, doors for the elevator car are not illustrated. Ordinary conventional power-operated doors which automatically open as the elevator car comes to a stop and which Iautomatically close when the elevator car is assigned to start may be employed. Alternatively, doors may be employed rwhich are spring-biased to closed position and which are manually opened by the passengers after the elevator car comes to a stop at any landing. I' At the expiration of its delay in dropout, which may be of the order of ve seconds, the relay A70T drops out to close its break contacts A70T1. These contacts A70T1 shunt the switch ASW and its associated contact ASWI and complete a starting circuit for the elevator car A in the same manner by which the operation of the car switch ASW previously completed a starting circuit.

As the elevator car A` reaches a terminal landing the switch ASW4 closes to maintain the delay relay A70T energized. When the elevator car A is assigned to leave the terminal landing, one of the sets of make contacts A931-1 or A941-1 closes to establish a shunt around the car switch ASW and its contact ASWI. This starts the elevator lcar A in the same manner by which it was started previously through operation of the car switch ASW.

Although the invention has been described with reference to certain specic embodiments thereof, numerous modifications falling within the, spirit and scope lof th invention are possible.

We claim as our invention:

1. In an elevator system for a structure having a iirst terminal landing, a second terminal landing spaced vertically from 'the first 'terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of `elevator cars, means mounting each Aof the elevator cars for vertical movement relative to the structure to serve -thelandings, call registering means for registering calls for each of a plurality of the landings, control means for stopping each of the elevator cars 'at each landing approached by the elevator car for which `a call is registered which may be served by the approaching elevator car, and start-initiating means responsive 'to a predetermined condition occurring while a iirst one of the elevator cars is set for travel towards the first terminal iloor for assigning a second one of the elevator cars to start from the second terminal lioor, said predetermined condition requiring call registration by the call registering means for a landing between the first `one of the elevator cars and the second terminal landing and location of the iir'st one of the elevator cars at any position in a predetermined zone containing a plurality of said landings adjacent to the rst terminal landing and spaced from the second terminal landing by a plurality of landings.

2. In an elevator system for a structure having a first terminal landing,V a second terminal landing spaced vertically from the rst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the structure to serve the landings, landing-up-call registering means for registering calls for each of a plurality of the landings in the up direction, 1landing-down-cfall registering means for registering calls for each of a plurality of the landings in the down direction, car-call registering means for each of the elevator cars for registering calls for landings desired by elevator car passengers, control means for stopping each of the elevator cars at each landing approached by the elevator car for which a call is registered [which may be served by the approaching elevator car, and start-initiating means responsive to a predetermined condition occurring while a iirst one of the velevator cars is set for travel towards the irst terminal licor for assigning a second one of the elevator cars to startV from the second terminal door, said predetermined condition requiring call registration by Ithe landing call registering means for a landing between the iirst one of the elevator cars and the Vsecond terminal landing and location of the 'rst one of the elevator cars at any position in a predetermined zone containing a plurality of said landings adjacent to vthe first terminal landing and spaced from the second terminal landing by a plurality of landings.

3. In an elevator system for a structure having a first terminal landing, a second terminal landing spaced vertically from the first terminal landing and a plurality of vertically-spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the structure to serve the landings, call registering means for registering calls for each of a plurality of the landings, control means for stopping each of the elevator cars at each landing approached by the elevator car for which Ia -call is registered which may be served by the approaching elevator car, dispatching means for dispatching successive ones of said elevator cars from the first term-inal landing at timed intervals, and means responsive to the conditioning at the same time of a predetermined number of the elevator 4cars for travel towards the second terminal landing for altering the length of said intervals, said last-named means being effective for altering the length of said intervals while the elevator cars are displaced substantially from the iirst terminal landing.

4. In an elevator system `for va structure having a iirs't terminal landing vva second terminal landing spaced vertically from the iirst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each ofthe elevator cars for vertical movement relative to the structure to serve the landings, landingup-ca'll registering means for registering calls for each of a plurality of the landings in the up direction, landingdown-call registering means for registering lcalls for each of -a plurality of the landings in the down direction, carcall registering means for each of the elevator cars for registering calls for landings desired by elevator car passengers, control means for stopping each of the elevator cars at each landingg'approa-ched by the elevator car for which a kcall is registered which may be served by the approaching elevator car, dispatching means for dispatching successive vones vof said elevator cars from the nrst terminal landing with `a time interval between each pair of successively-dispatched elevator ears, and means res'ponsive to the conditioning of all of said elevator cars at the same time 'for movement towards the second terminal landing for increasing the magnitude of said time interval.

5. In an elevator 'system for a structure having a rst terminal landing ya second terminal landing spaced vertically from the irst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the structure to serve the landings, landing-up-c'all registering means for registering calls for each of a plurality of the landings in the up direction, landingdown-call registering means for registering calls for each of a plurality of the landings in the down direction, carcall registering means for each of the elevator cars for registering calls for landings desired by elevator car passengers, control means for stopping each of the elevator cars at each landing approached by the elevator car for which a -call is registered which may be served by the approaching elevator car, and dispatching means responsive to call registration by a nrst part only of the call registering means for dispatching successive ones of said elevator cars from the iirst terminal landing with a time interval between each pair or' successively-disparched elevator cars, said dispatching means being inetective to dispatch one of the elevator cars in response to call registration by a second part only of the call registering means.

6. In an elevator system for -a structure having a iirst terminal landing, :a second terminal landing spaced vertically from the rst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the' structure to serve the landings, landing-upcall registering means for registering calls for each of a plurality ,of the landings in the up direction, landingdown-call registering means for registering calls for each of a plurality of the landings in the down direction, carcall registering means for each of the elevator cars for registering calls for landings desired by elevator car passengers, control means for stopping each of the elevator cars at each landing approached by the elevator car for which a call is registered which may be served by the approaching elevator car, and time dispatching means responsive to call registration by the landng-up-call registering means for dispatching successive ones of said elevator cars from the lower one of the terminal landings with a time interval between each pair of successively dispatched elevator cars, said time dispatching means being ineffective to dispatch said elevator cars in response to call registration by the landing-down-call registering means.

7. In an elevator system for a structure having a iirst terminal landing, a second terminal landing spaced vertically from the iirst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, `a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the structure to serve the landings, landingup-call registering means for registering -calls for each of a plurality of the landings in the up direction, landingdown-call registering means for registering calls for each of a plurality of the landings in the down direction, carcall registering means for each of the elevator cars for registering calls for landings desired by elevator car pas'- sengers, control means for stopping each of the elevator cars at each landing approached by the elevator car for which a call is registered which may be served by the approaching elevator car, and time dispatching means responsive to 'call registration by the landing-down-call registering means for dispatching successive ones of said elevator cars from the upper one of the terminal landings with a time interval between each pair of successively dispatched elevator cars, said time dispatching means being ineffective to dispatch said elevator cars in response to call registration by the landing-up-call registering means.

8. In an elevator system for a structure having a rst terminal landing, a second terminal landing spaced vertically from the rst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the structure to serve the landings, landiug-up-call registering means for registering calls for each of a plurality of the landings in the up direction, landingdown-call registering means for registering calls for each of a plurality of the landings in the down direction, carcall registering means for each of the elevator cars for registering calls for landings desired by elevator car passengers, control means for stopping each of the elevator cars at each landing approached by the elevator car for which a call is registered which may be served by the approaching elevator car, and time dispatching means responsive to call registration by the car-call registering means for dispatching successive ones of said elevator cars from the rst one of the terminal landings with a time interval between each pair of successively dispatched elevator cars, said time dispatching means being ineffective to dispatch said elevator cars in response to call registration by the landing-call registering means requiring travel towards the rst terminal landing.

9. in an elevator system for a structure having a first terminal landing, a second terminal landing spaced vertically from the iirst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the structure to serve the landings, landingup-call registering means for registering calls for each of a plurality of the landings in the up direction, landingdown-call registering means for registering calls for each of a plurality of the landings in the down direction, carcall registering means for each of the elevator cars for registering calls for landings desired by elevator car passengers, control means for stopping each of the elevat-or cars at each landing approached by the elevator car for which a call is registered which may be served by the approaching elevator car, and time dispatching means responsive to call registration by the landing-upcall registering means or by the car-call registering means of the car to be dispatched for dispatching successive ones of said elevator cars from the lower one of the terminal landings with a time interval between each pair of successively dispatched elevator cars, said time dispatching means being ineffective to dispatch said elevator cars in response to call registration by the landingdown-call registering means.

10. In an elevator system for a structure having a first terminal landing, a second terminal landing spaced vertically from the iirst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the structure to serve the landings, landing-up-call registering means for registering calls for each of a plurality of the landings in the up direction, landing-down-call registering means for registering calls for each of a plurality of the landings in the down direction, car-call registering means for each of the elevator cars for registering calls for landings desired by elevator car passengers, control means for stopping each of the elevator cars at each landing approached by the elevator car for which a call is registered which may be served by the approaching elevator car, and time dispatching means responsive to call registration by the landing-up-call registering means or by the car-call registering means of the car to be dispatched for dispatching successive ones of said elevator cars from the lower one of the terminal landings with a time interval between each pair of successively dispatched elevator cars, said time dispatching means being inelective to` dispatch said elevator cars in response to call registration by the landng-down-call registering means.

1l. In an elevator system for a structure having a rst terminal landing, a second terminal landing spaced vertically from the rst terminal landing and a plurality of vertically spaced intermediate landings intermediate the terminal landings, a plurality of elevator cars, means mounting each of the elevator cars for vertical movement relative to the structure to serve the landings, dispatching means for dispatching a iirst one of said elevator cars from the lirst terminal landing, said dispatching means being ineffective until a second one of the elevator cars lis located at any point in a zone of landings adjacent the second terminal landing, said zone including less than the full number of said landings.

No references cited. 

